The present invention relates to improvements in facilities for maintaining drains in commercial kitchens. This application contains certain subject matter in common with application Ser. No. 09/843,302 filed Apr. 25, 2001 now pending, the entire disclosure of which is hereby incorporated by reference.
In cooking environments, various items are discharged into a drain, not the least of which is grease, a by-product from cooking and washing. Grease in particular can be a source of problems, because when it cools, it can congeal and solidify, forming a solid having the capability of blocking or constricting the drain. Such grease blockage can build up over time, so it does not usually represent a discrete blockage event, but rather an accretion of congealed grease on the insides of the drains that, over time, narrows the flow path through the drain. This leads to the possibility of slow flow and, more particularly, to a possible blockage caused by a small article that would not block an unrestricted drain.
In addition, grease/water mixtures disposed directly into sewer lines burden municipal sewage systems since the grease builds up in sewer lines and on equipment in sewage treatment plants. To offset maintenance costs resulting from direct grease discharges into municipal sewers, municipal authorities assess surcharges against commercial food preparation operations that directly discharge grease/water mixtures.
Most food disposal installations in commercial kitchens involve a pre-rinse station in the dishwashing area. Dishes arriving from the dining area are first brought to the pre-rinse station where the food solids are rinsed into the pre-rinse sink and drain into the food disposal. Currently available technology does not provide for the separation of grease and oils prior to maceration by the food disposal unit. These flows frequently harbor high levels of fats (from salad dressings, butter, margarine, and fatty food scraps). As a result, food disposals are banned from commercial usage in numerous cities in the USA and around the world.
The advantages of garbage/food disposals are well known, so that the banning of such equipment brings additional problems of waste disposal, hygiene, and sanitation to commercial kitchen operations. Such operations need a solution to the problem of complying with sewer district needs while avoiding these untoward consequences.
Another problem that the commercial kitchens have is a lack of room under the sink for much equipment to extend downwardly below the drain of the sink. The normal location for a food disposer is that location. A need has arisen for improvement of space usage under the sink, while providing the other advantages of the oil/grease separation from the effluent flowing from the sink drain.
The present invention fulfills this need in the art by providing a food disposal system for installation on a drain of a commercial kitchen sink including a housing for collecting effluent flows containing water and solids from the drain, an opening from the housing other than downwardly when the housing is mounted to the drain, a macerating pump having an inlet connected to the opening of the housing and having an outlet connected to a sanitary drain, and a controller for effecting the operation of the macerating pump.
A preferred embodiment also includes a greasy water outlet from the housing extending to an oil/grease separator and located above the opening, a hot water backflush source discharging into the housing for enabling hot water to flow into the housing, and a sensor for sensing an accumulation of oil/grease in the housing.
Typically, a screen is interposed between the outlet and the housing. The hot water backflush source directs hot water to melt congealed grease on the screen.
The housing may include a chute to deflect water and solids entering the housing laterally, the macerating pump inlet may be located below a chute bottom, and the outlet to the sanitary drain may include a channel extending upwardly from the macerating pump.
The oil/grease separator may include a further macerating pump to macerate solids that may travel to the oil/grease separator.
The controller may be a timed controller that effects controlled operation of the hot water backflush. The controller may effect operation of the hot water backflush when the sensor senses an accumulation of oil/grease in the housing. The controller may effect sequenced operation of the hot water backflush and macerating pump in response to the sensor sensing an accumulation of oil/grease in the housing. Desirably, the greasy water outlet defines a static water level, and the sensor is located in the outlet above the static water level so that it senses a raised water level caused by an accumulation of oil/grease. The outlet to the sanitary drain may include a channel extending upwardly to define a secondary static water level, with the sensor located below the secondary static water level. The controller may actuate the hot water backflush followed by the macerating pump. A preferred embodiment also includes a cold water source actuable to introduce cold water into the housing when the macerating pump is operated.
The controller may be an operator-actuable switch. The backflush and macerating pumps may be actuated for preset times. Alternatively, the hot water backflush continues until a sensor indicates accumulated oil/grease has diminished.
Desirably, the opening from the housing to the macerating pump is oriented upwardly so that water and solids are drawn upwardly when the pump is operated.
The invention also provides a fitting for installation on a drain of a commercial kitchen sink to enable segregation of oil/grease from effluent flows from the drain including a housing adapted for collecting effluent flows containing water, oil/grease, and solids from the drain, an upwardly oriented opening on the housing adapted to be connected to a macerating pump, a greasy water outlet on the housing above the opening adapted to be connected to an oil/grease separator, and a hot water backflush fitting adapted to be connected to a hot water source for enabling hot water to flow into the housing.
The invention also provides a method of segregation of oil/grease from effluent flows of a drain of a commercial kitchen sink including draining the effluent flow containing water, oil/grease, and solids from a commercial kitchen sink to a housing below the sink, allowing separation of oil/grease from heavier components of the effluent flow to take place in the housing, directing segregated oil/grease and water from the housing to an oil/grease separator, and periodically operating a macerating pump having an inlet connected to the housing to macerate and pump the heavier components upwardly out of the housing and direct the heavier components to a sanitary drain maintaining a static water level at an elevation in the housing above the inlet to the macerating pump and wherein directing the oil/grease and water includes permitting gravitational flow of the oil/grease and water from the housing at the static water level. In the method the gravitational flow of the oil/grease and water may be from a height in the housing below a secondary static water level. The gravitational separation of components of the effluent flow may include permitting heavy solids to travel down a chute above the inlet to the macerating pump. Allowing separation of oil/grease from heavier components of the effluent flow may include screening solids from traveling with the oil/grease.
The method may also include periodically directing hot water flows into the housing to melt and loosen grease from the screen. The hot water may be directed into the housing when a water level sensor indicates a rising water level. The macerating pump may be operated after the hot water is directed into the housing. Cold water may be introduced into the housing when the macerating pump is operated.
The invention also provides a food disposal system for installation on a drain of a commercial kitchen sink to enable segregation of oil/grease from effluent flows from the drain including a housing for collecting effluent flows containing water, oil/grease, and solids from the drain, a macerating pump having an inlet connected to an upwardly directed opening of the housing and having an outlet connected to a sanitary drain, a greasy water outlet extending to an oil/grease separator from the housing above the macerating pump inlet to enable oil/grease and water to exit the housing, means for maintaining the flow of oil/grease and water through the greasy water outlet, and means for effecting the operation of the macerating pump.